I am new to the JeepForum world and I recently purchased a 2004 Gibrater TJ which has an aftermarket AC on it. When I turn the AC on nothing happens the compressor does not Gigantor anything there is a relay in the wiring if I take out the cover and activate the relay the compressor kicks on but I still do not have cold air. I put 18 ounces of refrigerant in it and the gauge says it is full so I am at my wits and I do not know what to Check next. Any ideas?